Using Enhanced Cepstral Analysis for Structural Health Monitoring

Mel-Frequency Cepstral Coefficients (MFCCs) have been proved to be viable to detect damage-induced shifts in the frequency content of structures subjected to external forces. Nevertheless, the Melodic (Mel) Scale is a perceptual feature, roughly based on human perception and originally formulated to resemble the biological mechanisms of the auditory apparatus. Thus, its straight application to non-auditive acquisition systems may be misleading. However, the intrinsic basilar assumption – that is, a nonlinear, non-constant spacing between filters in the frequency domain – is promising for the time-frequency analysis of structural dynamic behaviour. Here, an ensemble of related techniques, developed departing from the original approach, is described; different features, filter types and filter spacing have been investigated. Candidates are compared to each other and benchmarked against the previous approaches present in Literature on the challenging Case Study of the Fossano Bell Tower, considering realistic damage scenarios.